1. DNA PACKAGING

3. 8 histones make up the nucleosome core DNA wraps twice around the 8 histones Histone 1 helps maintain the nucleosome DNA is negatively charged & histones are positively charged Single human DNA molecule in a chromosome may be 4 cm long

4. A nucleosome consists of 2 molecules of each of 4 different histones The fifth histone leads to further wrapping of the DNA molecule Wrapping brings about a regulation of transcription allowing only certain

6. REPETITIVE SEQUENCES Dispersed regions of repetitive DNA are called satellite DNA (45%) They are not significant for coding But, they are transposable This means they can move from one genome location to another

8. STRUCTURAL DNA Highly coiled DNA that does not code (20%) Found around the centromere & ends of chromosomes at the telomeres Pseudogenes do not seem to have a function, probably due to mutation (2%)

9. PROTEIN-CODING GENES Exons – code proteins (1-2%) Introns (24%)